1. Field of the Invention
The present invention relates in general to a pedal device such as a brake pedal device and an accelerator pedal device, and more particularly to an improved adjustable pedal device wherein the non-operated position of an operating portion of a pedal is adjustable.
2. Discussion of Related Art
There is known an adjustable pedal device including (a) a pedal having (i) a pivotal member which is supported by a bracket such that the pivotal member is pivotable about a support shaft, and (ii) a pedal member disposed movably relative to the pivotal member in a sliding plane perpendicular to the support shaft, the pedal member having an operating portion at which the pedal member is operated so that the pedal member and the pivotal member are pivoted together about the support shaft, (b) a guiding device having (i) a pair of guide slots formed through one of the pivotal member and the pedal member, and (ii) a pair of guide pieces which are movable with the other of the pivotal member and the pedal member and which engage the pair of guide slots, respectively, to guide a movement of the pedal member relative to the pivotal member along a predetermined path, and (c) an adjusting device arranged to operatively connect the pedal member and the pivotal member, and operable to move the pedal member relative to the pivotal member so as to establish a desired relative position between the pedal member and the pivotal member, and to hold the pedal member and the pivotal member at the desired relative position. U.S. Pat. No. 6,289,761 discloses an example of an adjustable pedal device of this type for an automotive vehicle, which is constructed as shown in FIG. 5. In this adjustable pedal device, a pivotal member or link 104 supported pivotally by a support shaft or pin 102 fixed to a bracket 100 has two arcuate guide slots 106 and 108 and one linear guide slot 110, and a pedal member or arm 118 is connected to the pivotal member 104 such that the pedal member 118 is movable relative to the pivotal member 104 through guide pieces or pins 112, 114, 116 which are held in sliding engagement with the respective guide slots 106, 108, 110. The pivotal member 104 is provided with an electric motor 122, and a feedscrew or drive screw 120 which is disposed so as to extend in parallel with the linear guide slot 110 and rotated by the electric motor 122. The feedscrew 120 is held in engagement with the guide piece 116. With a rotary motion of the feedscrew 120 by the electric motor 122, the pedal member 118 is moved relative to the pivotal member 104, to a desired position between a fully advanced position (forwardest position) indicated by solid line in FIG. 5, and a fully retracted position (rearmost position) indicated by one-dot chain line. The guide slots 106, 108, 110 and the guide pieces 112, 114, 116 cooperate to constitute a guiding device, while the guide piece 116, the feedscrew 120 and the electric motor 122 cooperate to constitute an adjusting device operable to adjust the non-operated position of the pedal member 118 in the longitudinal direction of the vehicle.
However, this known adjustable pedal device requires high degrees of positioning accuracy (e.g. parallelism) and dimensional accuracy of the components, leading to a problem of a high cost of manufacture, due to the provisions of the three guide slots 106, 108, 110 and the corresponding three guide pieces 112, 114, 116 to guide the pedal member 118, and due to the arcuate shape of the two guide slots 106, 108 and the provision of the feedscrew 120 parallel to the linear guide slot 110 such that the feedscrew 120 is fixed to the pivotal member 104 by fastening means 126 through a suitable mount 124. The known pedal device has another problem that the guide pieces 112, 114, 116 having a cylindrical shape have a comparatively small surface area of contact with the surfaces of the guide slots 106, 108, 110, and an accordingly high pressure of contact with the surfaces of the guide slots due to a reaction force produced upon depression of the pedal member 118, resulting in easy deformation and wearing of the guide pieces 112, 114, 116 and the guide slots 106, 108, 110, and an accordingly low degree of durability of the pedal device.